DarG
05/05/2007, 12:05 PM
This doesn't involve any brand at all, just a question that applies to nearly all, if not all, Metal Halide / Flourescent combination fixtures.
There are quite a few of them too. If the Halide bulbs are generally supposed to be somewhere in the 8" - 12" off the water range and the Flourescents are generally siupposed to be 4" off the water ... how are these fixtures supposed to "work" efficiently? I mean, it would depend on the reflector for the Halides but if you placed the flourescents 4 inches from the water, then the Halides are going to be too close. They will be a couple inches higher than the Flourescents because they are usually recessed up into the fixture at the top of their reflector. But that wouldnt put them up high enough to where they should be. And if you raise the fixture so the Halides are at the "right" height, the flourescents are going to be too high up, maybe even way too high if 10 - 12" is best for the particular halides in the fixture.
So, it would seem that there is no way to maximize the effectiveness of these combo fixtures. Preference would seemingly go to the Halides since they have the potential to provide the majority of the light in these set-ups (also heat issues may come into play as well as salt spray on hot bulbs for the non-sheilded units). So, what does that make the Flourescents in these fixtures? Mainly color rendering and not really par rendering? How effective is a T5, for example, if it is 6-7" above the water? Or a PC or VHO?
Am I missing something? What do people with these fixtures generally do as far as height? Go with the Halide specs? With the Flourescent specs? Or compromise to an in between point?
There are quite a few of them too. If the Halide bulbs are generally supposed to be somewhere in the 8" - 12" off the water range and the Flourescents are generally siupposed to be 4" off the water ... how are these fixtures supposed to "work" efficiently? I mean, it would depend on the reflector for the Halides but if you placed the flourescents 4 inches from the water, then the Halides are going to be too close. They will be a couple inches higher than the Flourescents because they are usually recessed up into the fixture at the top of their reflector. But that wouldnt put them up high enough to where they should be. And if you raise the fixture so the Halides are at the "right" height, the flourescents are going to be too high up, maybe even way too high if 10 - 12" is best for the particular halides in the fixture.
So, it would seem that there is no way to maximize the effectiveness of these combo fixtures. Preference would seemingly go to the Halides since they have the potential to provide the majority of the light in these set-ups (also heat issues may come into play as well as salt spray on hot bulbs for the non-sheilded units). So, what does that make the Flourescents in these fixtures? Mainly color rendering and not really par rendering? How effective is a T5, for example, if it is 6-7" above the water? Or a PC or VHO?
Am I missing something? What do people with these fixtures generally do as far as height? Go with the Halide specs? With the Flourescent specs? Or compromise to an in between point?